Dual SIM: can't tether with sim1 if sim2 is present

With only one sim inserted in slot 1, I have everything set up properly and I can both use internet from the phone and do wifi or usb tethering.

However, if I ALSO add another SIM to slot 2 (which belongs to another operator whose plan probably does not allow tethering), I can't do tethering any more!!!

Is there a workaround?

My only workaround, currently, is to disable sim2 (and I need to turn Airplane mode on and off so that the change takes effect), so then I can do tethering, and when I'm done with the tethering, I re-enable sim2. But obviously that means that sim2 is offline while using tethering, meaning for example I won't receive calls or sms's on sim2.

I have read around there that there is a bug in Android 4.1-4-2 which silently switches to a different APN when tethering. So I edited ALL the APNs in settings to the same configuration of the one I'm using. The effect of that (curiously) was that even the APNs that were listed under "slot 2" have been automagically moved to "slot 1", so there's no APN now under Slot2. Yet, this didn't solve my issue.
I don't want to use sim2 for tethering, nor for data. I just want to be able to do tethering using sim1 whether or not sim2 is present and enabled.

Re: Dual SIM: can't tether with sim1 if sim2 is present

Hello to all,

I have a similar problem with my M8 dual SIM. I have two carriers from two different countries. Living close to the border makes this phone priceless for me !

With Android 4.4.4 I can easily switch each SIM on and off and decide on which SIM data should be used. For SIM1 data works fine but not for SIM2 even if I disabled SIM1 and I see that data settings have switched to SIM2. I just don't get any data connection at all. Voice works fine but the data icon does not even appear on the top bar of the phone.
I checked the APN settings for this particular carrier and all is set properly.